Technical and environmental assessment of selective recovery of tin and lead from waste solder alloy using direct anodic oxidation

Abstract The current study aimed the selective recovery of tin and lead from waste Sn Pb alloy obtained as a secondary stream in the recovery process of copper from waste printed circuit boards. The recovery of the two metals was achieved through selective direct anodic dissolution of the waste Sn Pb alloy samples in H 2 SO 4 solutions coupled with the simultaneous electrowinning of a tin rich cathodic deposit. The optimal operating conditions were identified based on the influence of current density, H 2 SO 4 concentration and electrolyte flow rate on the main technical performance indicators. The most favorable operating conditions for the electrochemical process were obtained at 0.5 M H 2 SO 4 concentrations, 60 A/m 2 current density and at a flow rate of 45 mL/min. Based on the experimental results the process was scaled-up, modeled and simulated using process flow modeling software CHEMCAD. The mass balance data corresponding to the recycling of 100 kg/h waste solder in the identified optimal operating conditions was used for the environmental assessment of the process. The General Effect Indices, for the input and output streams of the process, obtained through the Biwer-Heinzle method indicate that the developed recovery process it is not only efficient but environmental friendly as well.